Shift register control for a paper finishing machine



. 1, 1964 c. P. GRANT ETAL SHIFT REGISTER comm. Foa A PAPER FINISHING MACHINE Filed March 1s, 1961 ATTORNEYS UnitedStates Patent O 3,159,068 SHIFT REGISTER CONTROL FOR A PAPER FINISIIING MACHINE Clyde Percy Grant, Gorham, and Merton Arthur Look, Portland, Maine, assignors to S. D. Warren Company, Boston, Mass., a corporation of Massachusetts' Filed Mar. 13, 1961, Ser. No. 95,385 2 Claims. (Cl. 83-106) This invention relates generally to vshift register con-Y trol systerns for continuously operating machines which' inspect a product and require the actuation of mechanism for rejecting defective portions of the product at a station which is downstream from the inspection stand at which the defect is detected.

More specifically this invention relates to a'shftregister control system for a paper finishing machine to inspect a strand of paper prior yto its 'being cut into sheets and the operation of a reject gate to reject those sheets which contain a defect previously detected.

Prior shift register control systems for this purpose have provided synchronization between control of the reject gate and the output of a shift register, synchronized with integral units of the product inspected ,such as the individual sheets cut from the moving web. Arrangements of` this type must be operated sufficiently in advance of the head of the oncoming defective sheet to be sure of always rejecting such defective sheets. These prior systems have-further been restricted to operation in the space between the trailing ed-ge of one sheet and the leadingedge of the next subsequent sheet with the result that `often to insure rejection of all defective sheets `some good sheets were also rejected.

The present invention provides improved operation of a shift register control of a reject mechanism by providing synchronization of the operation with the position of the leading edge of a sheet and the trailing edge of the sheet in order that the reject gate may be opened only when required for rejecting a defective sheet. Improved control is obtained in accordance with the invention by providing accurately phased time impulses referenced to a fixed time position which'is invariant with the operating speed of the machine and hence provides precise control of` the reject gate no matter what speed the machine may be operated.

It is `accordingly an object of the ypresent invention to provide an improved Ashift .register control for reject mechanism.

Another object of the invention is to provide an improved phasing of the operating signals of a reject mechanism controlled by a shift register. i Y

,These and other objects ofthe invention will be apparent Yfrom Ythe following detailed description taken in conjunction with the accompanying drawing wherein:

f FIG. gl is ablock diagram of a vshift register control system for 4controlling the reject gate in a paper sheet .cuttingmachine; and j FIG. 2 is an elevation view of a phase control for the system of FIG. 1.

, The presentinvention will be described with reference to an automatic paper finishing machine disclosed and claimed in the copending application of Gilbert Forrester, 'Ser. No. 95,374 tiled March 13, v1961 and assigned to the assignee of the present invention.

`Referring now to FIG. l, a description of the shift register memory for operating the reject gate 36 will be ifdescribed. Referring to FIG. 1 the constructionpand (operation of the defect memory and reject gate control .wi-ll `be described. As previously stated suitable defect {detectors are employed to `inspect the web 16 and pro- Qduceanelectrieal signal when a defect is detected. For

ICS

156 are set to a ONE state by defect input signals thereto and are reset by the applicationof a reset pulse to `inputs 157', 158 respectively. Upon' the occurrence of a reset pulse to reset apreviously set stage or 156 an output pulse is produced which is the input signal to the first stage of six stage flip-flop shift registers 157, 158.

The shift registers 157, 158 operate conventionally to advance the state of each stage to the next subsequent stage upon the occurrence of a shift pulse input on lines 159, 160. Thus if a void is detected by.void detector 151, for example, the input memory flip-liep 155 is set and upon the occurrence of a shift pulse on line 159 the memory flip-nop 155 is reset and' the first stage of the shift register 157 is set. This action is repeated for each subsequent reset pulse on line 159 and hence the position of a set stage in the register 157 corresponds with the position of a defect in the web 16 a-t Aa point in the machine subsequent to thedefect stand 24.v In conventional shift register terminology the ONES in the registers 157, or 158 are advanced stage byv stage lupon the occurrence of the shift pulses on lines 159 or 160.

The shift pulses on lines 159 and 160 are derived in synchronism with the rotation of the cutter 2 8 butwith adjustable phase relative to an arbitrary zero point` suoh as the .positionwhere the cutter 28 en-gages the bed knife 27 to make a cut in the web 16. For this purpose the drive lfor the drum 29 is applied to drive rotary pulse generators 161,162.

The pulse generators l161, 162 may be constructed as rotary distributor-type mechanical contact devices with a fixed contact mounted on the housing and adjustable through 360 about the axis of rotation of the rotating contact. Preferably however the pulse. generators 161, 162 are constructed as shown in FIG. 2. In the pulse generator of FIG. 2 a cylindrical housing 171 is mounted for rotative adjustment by means of a worm gear 172, manually driven by means of a knob 174. vThe worm 172'engages gear teeth 175 on the housing 171. Mounted on a shaft 176 is a disc 177 having a narrow radial slot 178. Fixed tothe inner wall of the housing 171 andon one side of the disc is a light source 179. Aligned axially with the light source 179 on the opposite side of 'transiston With this arrangement a resolution of onehalf degree can readily be obtained. By pulse shaping the reproducibility of the pulse output with reference t0 rotation of shaft 176 can 'be maintained to any required degree of precision.

The ONES outputs of the last five stages of shift registers 157, 158 are connected to selector switches 1,81, 182 where wiper contacts 183, 184 can be adjusted toselect the output of any register stage after the first as the signal for con-trolling the reject gate 36. The wipers 183, 184 are connected as inputs to a NOR 185 in an AND gate 1,86. An additional manual input 187 is applied to the NOR 185 for manually operated rejection of sheets. The AND 186 additionally includes a NOR 188 having an input ,from a reject gate opening pulse generator 189. The outputs of NORS 185,188 are the inputs of a NOR 190. 'Ihe operation of the AND 186 produces an output Patented Dec. l,

signal to set a flip-flop 191 only if a ONE input to the NOR 185 is present when the pulse input to NOR 188 occurs.

The two ou-tputs of flip-flop 191 are used to controlthe reject gate 36 by alternately energizing a down solenoid 192 or an up solenoid 193. When the flip-flop 191 is set the up solenoid 193 is energized to raise the gate 36 and reject the next sheet. To close the gate 36 a closing timing pulse genera-tor -194 applies a reset pulse to the ip-op 191 thereby de-energizing the solenoid 193 and energizing the down solenoid 192.

The opening and closing pulse generators 189, 194 include rotary pulse generator devices 195, 196 similar to the devices 161, 162.

The operation of the shift register memory control will now be described. A defect passing the detector stand 24 causes a defect signal to appear at the input flip flop S or 156 of the shift register 157 or 158 associated with that type of defect. This flip-flop remains set after the defect detector voltage pulse has returned to zero and'is thus held or stored until the action of the shift pulse generators 161 or 162- causes it to shift to the next memory stage ofthe shift register.

The shift pulse generators 161, 162 andthe gate opening and closing pulse generators 189, 194 are all geared to the rotary cutter drum 29 and rotate in synchronism with it. One pulse per revolution is delivered from each generator 161, 162, 189, 194. The angular positions at which the pulses are generated can be adjusted at each individual generator throughout 360.- Since the paper web moves a distance equal to one sheet length during one l revolution of the rotary cutter drum 29, the pulse generators 161, 162, 189, 194 all deliver one pulse each per sheet length. The phase relationship between the various timing pulses depends upon the individual generator position adjustment made by rotating knob 174.

For any given sheet length the shift pulse generators 161, 162 vare adjusted so that the shift pulse occurs just asa projected or future cut line in the web 16 is at the respective detector location. Thus defect signals are stored in flip-flop 155 or 156 while the portion of the sheet subsequent to the defect passes'under a detector and are shifted to the next stage in the shift register as the tail of the defective sheet passes the detector. At the same instant, the input memory is reset and thus readied to receive defect signals, if any, during the passage of the next sheet.

The signal now representing a defective sheet, rather than appearingrandom intime as it does at the input to ip-ops 155 or 156, shifts from stage to stage of the registers 157 or 158 with each succeeding revolution of the rotary cutter drum 29. An `output from the shift register occurs at the shift instant but delayed from the input to the first `stage a time equal to that required for one sheet length of paper travel per stage of the register occurring before the output stage. The registers 157, 158 therefore accomplish only whole sheet length delays, the number of which depends upon which stage is selected as the output stage. j

Since the distance from detector to reject gate 36 is known, the number of revolutions of the cutter during 29 necessary to progress a given sheet from the detector to a position less than one4 sheet length before the reject gate 36 is also known. This number of revolutions is the number of stages that must be in the shift registers 157, 158. One extra stage 155 or 156 is for input storage of the defect signal until the sheet tail reaches the detector location. Different sheet lengths will require different number of shifts since the distance from detector to gate 36 must be divided into an integral number of sheet lengths. The selector switches 183, 184 provide for this adjustment.

The defective sheet level signal from the shift registers 157, 158 appears at the input to AND 186 at the shift instant and remains until the next shift instant. At the instantlthis level appears the head of the defective sheet is less than one sheet length from the gate. The exact distance can readily be calculated by subtracting the product of sheet-length and number of shifts from the overall distance between detector 151 or 152 and reject gate 36. This distance less any distance the sheet travels during gate 36 actuation delay represents the maximum further delay that can take place and still make it possible to reject the sheet.

The delay or any por-tion of it can be accomplished through adjustment of the gate opening pulse generator 189 since the output from the AND 186 will net take place until the gate opening pulse from generator 189 occurs in conjunction with the shift register output. The signal from the AND 186 causes the output ip-flop 191 and power amplifier to energize the rejectl gate solenoid 193 and the reject gate 36 opens to reject the defective sheet. The reject gate 36 is closed by the next pulse of the closing pulse generator 194 which is adjusted to operate after a delay sufficient to permit the rejected sheet to be under positive control of the tape system 42.

FIG. 1 shows two output solenoids. Operation is similar if a single spring return solenoid valve or solenoid is used to open the gate. ln either case the gate up solcr noid is de-energized when the output flip-flop changes state.

Provision for manual rejection is possible by applying a manual reject pulse to the AND gate and holding it for coincidence with the gate opening pulse. If desired the gate closing pulse can be temporarily disabled by the manual pushbutton to prevent the gate from closing and reopening with each cycle.

The memory system just described provides for four delays from the time a defect is detected until the gate closes after rejecting the defective sheet.

These delays are:

(l) A delay in time equivalent to the time required for the passage of the paper a distance from the defect location tothe tail of the sheet containing it. This is the time existing between a detector output and the shift pulse instant. The delay automatically works in time with machine speed and occurrence of defect signal. (2) The shift register delay is equal ot the time required for the passage of a whole number of sheet lengths. The number (N) is the number of whole sheet lengths that exist between detector and gate. The delay is thus the time betwen the rst shift instant after the defect signal and shift constant N+1 after the"y defect signal.A (3) The third delay is a fractional sheet length delay. It is the time lag between the shift pulse and the gate opening pulse. v(4) The last delay is the time that the gate remains open. The interval between the gate opening and gate closing pulse is this delay. All delays are in terms of distance traveled. Thus the time is automatically varied with changes in machine speed, and adjustments for a given sheet length hold under all conditions of speed.

While a speeic embodiment of the invention has been disclosed, it will be apparent to those skilled in the art that various modifications thereof may be made without departing from the invention. Accordingly the invention is to be limited only by the scope of the appended claims.

We claim:

1. A reject gate control system for a paper rcutting machine comprising means for sensing defects in a moving paper web, a multiple stage shift register having a serial input storage stage responsive to said defects for registering defect signals in said storage stage, a shift pulse generator synchronized with the knife for cutting said web into sheets, means for adjusting the phase of said shift pulse generator relative to the cutting position of said knife, said generator connected and phased to shift said defect signals out of said storage stage into the first stage of said shift register at the time said web has moved to position the tail of the sheet containing said defect at the defect detecting means and thereafter successively through the stages of said register synchronized with the passage of integral sheet lengths through said machine, selective means for connecting to the output of a selected stage of said register, a second pulse generator for generating a timing pulse adjustably phased relative to said cutting position of said knife, gating means enabled by a defect signal output of said selected stage of said register and operable when enabled to pass said timing pulse from said second pulse generator, and means for operating said reject gate into reject position in response to timing pulses passed by said gating means.

2. Apparatus according to claim 1 and including a i third timing pulse generator for generating timing pulses References Cited in the le of this patent UNITED STATES PATENTS Camp Aug. 30, 1960 Walsh June 11, 1963 

1. A REJECT GATE CONTROL SYSTEM FOR A PAPER CUTTING MACHINE COMPRISING MEANS FOR SENSING DEFECTS IN A MOVING PAPER WEB, A MULTIPLE STAGE SHIFT REGISTER HAVING A SERIAL INPUT STORAGE STAGE RESPONSIVE TO SAID DEFECTS FOR REGISTERING DEFECT SIGNALS IN SAID STORAGE STAGE, A SHIFT PULSE GENERATOR SYNCHRONIZED WITH THE KNIFE FOR CUTTING SAID WEB INTO SHEETS, MEANS FOR ADJUSTING THE PHASE OF SAID SHIFT PULSE GENERATOR RELATIVE TO THE CUTTING POSITION OF SAID KNIFE, SAID GENERATOR CONNECTED AND PHASED TO SHIFT SAID DEFECT SIGNALS OUT OF SAID STORAGE STAGE INTO THE FIRST STAGE OF SAID SHIFT REGISTER AT THE TIME SAID WEB HAS MOVED TO POSITION THE TAIL OF THE SHEET CONTAINING SAID DEFECT AT THE DEFECT DETECTING MEANS AND THEREAFTER SUCCESSIVELY THROUGH THE STAGES OF SAID REGISTER SYNCHRONIZED WITH THE PASSAGE OF INTEGRAL SHEET LENGTHS THROUGH SAID MACHINE, SELECTIVE MEANS FOR CONNECTING TO THE OUTPUT OF A SELECTED STAGE OF SAID REGISTER, A SECOND PULSE GENERATOR FOR GENERATING A TIMING PULSE ADJUSTABLY PHASED RELATIVE TO SAID CUTTING POSITION OF SAID KNIFE, GATING MEANS ENABLED BY A DEFECT SIGNAL OUTPUT OF SAID SELECTED STAGE OF SAID REGISTER AND OPERABLE WHEN ENABLED TO PASS SAID TIMING PULSE FROM SAID SECOND PULSE GENERATOR, AND MEANS FOR OPERATING SAID REJECT GATE INTO REJECT POSITION IN RESPONSE TO TIMING PULSES PASSED BY SAID GATING MEANS. 